[Xen-devel] [PATCH 17/20] x86/ticketlock: clarify barrier in arch_spin_lock

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

From: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>

Make sure the barrier in arch_spin_lock is definitely in the code path.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
---
 arch/x86/include/asm/spinlock.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h
index 158b330..c7455e1 100644
--- a/arch/x86/include/asm/spinlock.h
+++ b/arch/x86/include/asm/spinlock.h
@@ -151,13 +151,13 @@ static __always_inline void arch_spin_lock(struct 
arch_spinlock *lock)
 
                do {
                        if (inc.head == inc.tail)
-                               return;
+                               goto out;
                        cpu_relax();
                        inc.head = ACCESS_ONCE(lock->tickets.head);
                } while (--count);
                __ticket_lock_spinning(lock, inc.tail);
        }
-       barrier();              /* make sure nothing creeps before the lock is 
taken */
+out:   barrier();              /* make sure nothing creeps before the lock is 
taken */
 }
 
 static __always_inline int arch_spin_trylock(arch_spinlock_t *lock)
-- 
1.7.2.3


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